The invention relates to an equalizing plate or platen for a vulcanizing press or other such presses, consisting of a top plate and a bottom plate which are joined flexibily together at their outer periphery and in the space between which a low-melting point metal alloy is hermetically sealed.
An equalizing plate of this kind is described in FR-PS 1,592,833. The equalizing plate consists of a pair of approximately parallel, continuous plates which are joined together at their margin. The inner space between the two plates is filled with a fluid metal alloy, and the object of using such an equalizing plate is a better transfer of heat to the material being vulcanized. Another purpose consists of achieving a uniform distribution of the pressure applied by the press plates.
Equalizing plates of this kind have not found widespread practical use, because, after only a short time in service, unacceptable deformations have appeared in the flexible plates. Furthermore, due to the frequent temperature fluctuations produced by operating conditions, considerable internal stresses are produced which in critical situations could result in fracture in the area where the two plates are joined together.